The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art.
When light is received by a retina, complex signal processing takes place within the layers of the retina. Visual signals encode the information in the form of electrical “spikes.” These electrical “spikes” are actually electro-chemical signals sent from ganglion cells to the visual cortex in the brain via the optic nerve. In some vision related diseases, the outer layers of the retina including the photoreceptors lose their function. However, the inner layers of the retina remain anatomically and functionally intact.
Advances have been made in the use of microphotodiode arrays and patterned stimulation electrodes as artificial retina devices. Such artificial retina devices are designed to address various vision related diseases such as retinal pigmentosa or macular degeneration or to augment normal vision. However, known artificial retina devices involve conventional electronics that are based on inorganic materials such as silicon or platinum/iridium oxide coated substrates. Such devices are not biocompatible or bio-stable and thus involve serious drawbacks to implantation in a human eye.
The drawbacks associated with traditional artificial retina devices are numerous. Such devices are known to cause serious gliosis in in-vivo cases as well as additional complications due to the mechanical incompatibility of the device with human tissue at the implant/tissue interface. In addition, such devices require bio-compatible electrodes in order to interface with human tissue and a video chip to process signals. Such devices further require an external power supply which may be provided via radio frequency signals or pulsed energy systems. In addition, traditional artificial retina devices have low visual acuity despite numerous advances in many areas (e.g., material, fabrication, energy supply, packaging, etc.). For example, traditional devices have allowed for a maximum of only 20/100 vision.